Occurrence of SAEs related to study participation or to a concurrent GSK medication/vaccine [ Time Frame: from screening (up to 21 days prior to Month 0) until Month 18. ] [ Designated as safety issue: No ]

Occurrence of any fatal SAEs [ Time Frame: from screening (up to 21 days prior to Month 0) until Month 18. ] [ Designated as safety issue: No ]

Subjects who the investigator believes that they can and will comply with the requirements of the protocol;

Male and female subjects at least 18 years old at the time of vaccination;

Subjects born before 1985 and not from a tropical region. Subjects born in 1985 or later and subjects born before 1985 in tropical regions must have a history of Varicella Zoster virus (VZV) infection or serological evidence of prior VZV infection;

Written informed consent obtained from the subject;

Female subjects of non-childbearing potential may be enrolled in the study; Non-childbearing potential is defined as current tubal ligation, hysterectomy, ovariectomy or post-menopause.

OR Female subjects of childbearing potential may be enrolled in the study, if the subject has practiced adequate contraception for 30 days prior to vaccination, and has a negative pregnancy test on the day of vaccination, and has agreed to continue adequate contraception during the entire treatment period and for 2 months after completion of the vaccination series;

Known to be human immunodeficiency virus-1 (HIV-1) infected, diagnosed at least 1 year prior to enrolment;

For the antiretroviral therapyART High CD4 and ART Low CD4 cohorts:

Stable on ART for at least one year

CD4 T cell count >= 50 cells /mm3 at screening

Undetectable VL at screening;

For the non-ART High CD4 cohort:

ART-naïve subjects who have never received anti-retroviral therapy after HIV diagnosis and for whom commencement of ART is not expected based on current assessment within next seven months;

HIV VL >= 1000 copies/mL and <= 100 000 copies/mL at screening

CD4 T cell count >= 500 cells/mm3 at screening.

Exclusion Criteria:

Use of any investigational or non-registered product other than the study vaccine within 30 days preceding the first dose of study vaccine, or planned use during the study period;

Vaccination against varicella or herpes zoster (HZ) within the previous 12 months;

Occurrence of a varicella or HZ episode within the previous 12 months;

History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. Additionally, consider allergic reactions to other material or equipment related to study participation. Please note, the vaccine and vials in this study do not contain latex;

Has currently an Acquired Immunodeficiency Syndrome (AIDS) defining condition;

Opportunistic infection or AIDS-associated malignancy in the previous year;

Any confirmed or suspected immunosuppressive or immunodeficient condition resulting from disease other than HIV infection or immunosuppressive/cytotoxic therapy;

Administration of immunoglobulins, and/or any blood products within 90 days preceding the first dose of study vaccine/placebo or planned administration during the study period;

Chronic administration of immunosuppressive or other immune-modifying drugs within 6 months prior to the first vaccine dose;

Administration and/or planned administration of a vaccine not foreseen by the study protocol within 30 days before dose 1, dose 2 and/or 3 of vaccine and/or within 30 days after any dose. However, licensed non-replicating vaccines may be administered up to 8 days prior to dose 1, 2 and/or 3, and/or at least 14 days after any dose of study vaccine;

Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational product;

Acute disease at the time of enrolment;

Any contraindication to receiving intramuscular injections;

Any condition or illness which might interfere with the evaluation of the safety or immunogenicity of the vaccine;

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01165203